Design,analysis and application of large temperature difference cooling systems

doi:10.3969/j.issn.1674-1951.2021.10.010

Abstract

Abstract:

In the analysis on the key factors affecting energy consumption of large temperature difference cooling systems powered by distributed energy,the effects of large temperature difference cooling on the evaporating temperature,COP（Coefficient of Performance）and auxiliary terminal equipment of chillers are studied.According to the calculation results,with the expansion of the temperature difference between supply and return and the drop of supply water temperature in a large temperature difference cooling system,the evaporating temperature of the chiller will decrease and the chiller's energy consumption will increase,but the energy consumption of the chilled water pumps will fall significantly.The energy consumption reduction realized by the large temperature difference cooling system has to be calculated on the premise of ensuring the operation of the chillers and fan coil units.This normal operation can be realized by lowering the cooling supply temperature,increasing the number of coils and adding anti-freezing measures.There is an actual project installed 15 large temperature difference chillers with 130 MW cooling load.The 15 refrigeration devices include three sets of 8 600 kW centrifugal chillers in series with lithium bromide units, nine sets of 7 384 kW centrifugal chillers and three sets of 2 813 kW centrifugal chillers.Compared with the conventional refrigeration system （7/12 ℃）,the energy saved annually by the large temperature difference refrigeration system （3/13 ℃） grows by about 1.75 GW·h.This analysis provides a reference for subsequent similar projects.

Key words: distributed energy, large temperature difference cooling system, chiller, temperature difference between supply and return water, evaporating temperature

CLC Number:

TK01⁺9

WEI Ruhua, WANG Yifeng. Design,analysis and application of large temperature difference cooling systems[J]. Huadian Technology, 2021, 43(10): 80-85.

Figures/Tables 9

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温差	供水温度
温差	3.00	4.00	5.00	6.00	7.00	8.00	9.00	10.00
5.00	1.12	2.12	3.12	4.12	5.12	6.12	7.12	8.12
6.00	0.90	1.90	2.90	3.90	4.90	5.90	6.90	7.90
7.00	0.70	1.70	2.70	3.70	4.70	5.70	6.70	7.70
8.00	0.52	1.52	2.52	3.52	4.52	5.52	6.52	7.52
9.00	0.34	1.34	2.34	3.34	4.34	5.34	6.34	7.34
10.00	0.17	1.17	2.17	3.17	4.17	5.17	6.17	7.17

水泵类型	规格参数	数量/台
串联离心机冷冻水泵	变频泵,流量800 m³/h,扬程15 m,电机功率50 kW/380 V	4
2100RT大温差离心式冷水机组冷冻水泵	变频泵,流量700 m³/h,扬程20 m,电机功率60 kW/380 V	12
800RT大温差离心式冷水机组冷冻水泵	变频泵,流量300 m³/h,扬程20 m,电机功率30 kW/380 V	4

负荷分布/%	天数/d	常规供冷系统能耗/(kW·h)		大温差供冷系统能耗/(kW·h)
负荷分布/%	天数/d	冷水机组	冷冻水泵	冷水机组	冷冻水泵
100.0	25	4 824 831	804 762	4 997 834	253 500
75.0	55	7 234 975	1 327 857	7 494 396	418 275
50.0	70	4 981 079	1 126 667	5 159 683	354 900
25.0	30	1 004 919	241 429	1 040 952	76 050
年运行总能耗		21 546 519		19 795 590
年节约能耗		1 750 929